Hydraulic unit



C. S. LEE.l

HYDRAULIC UNIT July 3, 1951 3 Sheets-Sheet 1 Filed Sept. 25, 1948 July 3, 1951 c. s. LEE 2,559,125

HYDRAULIC UNIT Filed Sept. 23. 1948 .'5 Sl'leecs-Sheei'I 2 ,Z ,2 fw, f/i /54 fm? /M JNVENTOR. MAIN I 5MM/j C21-fe $468.

JM "4/,25 )24 )ff BY 4g l dgn@ July 3, 1951 c. s. LEE 2,559,125

HYDRAULIC UNITI1 .Patented July 3, 1,951

UNITED STATES PATENT OFFICE Claims.

This invention relates broadly to new and useful improvements in hydraulic machines and more particularly to a novel mounting arrangement for the instrumentalities which control the operating cycle of such machines.

An important object of the present invention is to provide a control panel assembly for hydraulically operated machines, which panel includes all or substantially all of the equipment or instrumentalities for operating machines.

Another object of the invention is to provide a control panel assembly of the above-mentioned character wherein the instrumentalities are all mounted on and associated With the panel so as to provide a unitary assembly.

Still another object of the invention is to provide a control panel assembly of the abovementioned character that can be easily and expeditiously mounted on or removed from the machine.

Yet another object of the invention is to provide a control panel assembly of the above-mentioned character wherein certain of the instrumentalities are uniquely located on the panel so as to connect or align automatically with co-operative machine parts or elements when the assembly is mounted on the machine.

A further object of the invention is to provide a novel arrangement for the control parts of hydraulic machines on a mounting panel, which panel assembly is capable of standardization so that a panel assembly can be easily and quickly replaced by a substitute assembly in the event failure occurs in some part of the control equipment or in the event it is necessary to repair or replace any part of the control equipment.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the drawing forming a part of this specication and wherein like numerals are employed to designate like parts throughout the same,

Fig. l is a side elevational View of a hydraulically operated machine equipped with a control panel assembly embodying the present invention,

Fig. 2 is a longitudinal sectional view through the machine shown in Fig. 1,

Fig. 3 is a front elevational view of the panel assembly with the cover removed,

Fig. 4 is a top plan view thereof,

Fig. 5 is a diagrammatic View of the hydraulic circuit for controlling operation of the machine, and

Fig. 6 is a diagrammatic view of the electrical hydraulic instrumentalities.

Many automatic machine tools are operated hydraulically. Various instrumentalities such as pumps, valves, metering devices and control circuits are employed for each machine. The number and arrangement of these instrumentalities usually varies somewhat depending upon the nature of the machine and the operation to be performed.

Heretofore the various instrumentalities in the operating and control circuits have been mounted more or less indiscriminately on the machine. Apparently the location and mounting of each instrumentality has been determined primarily by convenience and the particular function it is to perform. As a result, the operating and control devices are disposed at various points over the entire machine, and a failure of one device renders the entire machine inoperative until the device can be repaired or replaced. Frequently, it is actually necessary to dismantle parts of the machine in order to gain access to a particular device. When this condition prevails, the machine is out of operation for a considerable period of time.

Further, there are many instances Where large automatic machines are made up of a number of small units, each of which performs a different operation on the Work. When one of the small units is rendered inoperative for any reason, the entire machine is out of commission. Thus the failure of a hydraulic pump, for example, on one of the small individual units, may render the entire machine inoperative for an entire day or longer.

When a machine is out of operation, production is curtailed and man hours are lost. Also, the loss of a key machine may aiect the operation and production of other machines in the plant. Thus, a solution to the problem of quickly making repairs on or replacing parts of the hydraulic and electrical operating and control circuits of these machines Will to a large extent obviate the above diinculties.

The present invention comprises a mounting arrangement for the various hydraulic and electrical instrumentalities which operate and control machines of the above-mentioned character. It is contemplated that all of the instrumentalities be mounted on a single panel and that the panel be arranged and mounted on the machine in such a Way that any instrumentalities which cooperate with parts of the machine will be automatically connected to or aligned with such parts when the panel is mounted on the machine. Also, it is contemplated that the various instrumentalities be uniquely combined and endless belts 32. 4pulleys 23 and 30 and endless belts 32.

correlated on the panel so that the various hydraulic and electrical circuits can be completed within the confines of the panel. By reason of this arrangement, it requires but a few minutes to mount or remove a panel. Since a large number of machines in a single plant will use identical control panels, it thus becomes expedient and practicable to maintain replacement panels. If a hydraulic pump or other instrumentality for operating or controlling one of the machines is rendered inoperative or faulty in operation for any reason, an entirely new or properly serviced panel assembly can be easily and quickly substituted for the panel assembly of such machine. The replacement can be accomplished in a few minutes and the machine will be out of service for only a very short time. The panel assembly having the faulty or inoperative equipment can then be reserviced at leisure.

In the drawing I have shown a hydraulically operated, electrically controlled machine which is typical of those for which the present invention is primarily adapted. The machine here shown comprises a head Iii mounted for longitudinal sliding movement on a base I2. A spindie |14 extends longitudinally through the head ID, and it is supported for rotation by bearings Y I6 and I8 in the end walls 2d and '22 of the head. VAt the forward end of the spindle I4 is a cou-r pling 2 which is adapted to receive a tool or tool holder (not shown) according to conventionalpractice. Surmounting the head Iii is a motor 2S which rotatably drives the spindle Ill through the medium of pulleys 28 and 3S and A guard 34 is provided for the Thus, a tool carried by the spindle I4 is rotatably driven by the motor 25, and the rotating tool can be advanced or retracted axially by moving the head Ill on the base I2.

In order to advance and retract the head IIJ positively on the base I2 I provide a hydraulic motor which includes a cylinder 36 xed on the head and a piston 38 fastened to the base I2. The cylinder is arranged with its axis parallel to the direction of travel of the head Ill. As best shown in Fig. 2, the cylinder 35 extends downwardly into the base I2 and receives the piston 38 having a piston rod lil which is fastened to the forward wall 42 of the base. Hydraulic liquid is admitted into or discharged from the cylinder 36 ahead of the piston 38 through a passage i4 and is admitted into or discharged from the cylinder behind the piston through a passage 4S. Since the piston 38 is stationary,

hydraulic liquid admitted into the cylinder 36 Y through passage M -will advance the cylinder to the left from the position shown in Fig. 2 and consequently the head I@ to which it is attached. Conversely, hydraulic liquid admitted into the cylinder 35 behind piston 38 retracts the cylinder and the associated head i9. In the draw- V ing, the head IG and cylinder 36 are shown fully retracted on the base I2.

In the machine here shown by way of illus-v tration, the head I S is hollow and serves as a v`tank or reservoir for the hydraulic liquid which conveniently may be charged thereto through a 'by sealing members 52 and 54 respectively. If

. tion.

4 necessary o1l desirable, suitable additional seals (not shown) may be provided around the bearings IB and I8.

As suggested, the hydraulic apparatus for directing and controlling the flow of liquid to the cylinder 35 and electrical apparatus for operating the hydraulic equipment are grouped t0- gether on a panel assembly 56, and the latter is ybolted or otherwise fastened to the head I0 over an opening 53 in one side thereof. Suitable sealing strips 5l' are provided around the margin of the panel to prevent leakage of hydraulic liquid from the tank. Since the panel assembly 56 is mounted on the outside of head IIJ, it is readily accessible and can be easily and quickly attached to or removed from the machine. All of the hydraulic and electrical instrumentalities are mounted on the panel and consequently are applied to or removed from the machine with the panel assembly.

All hydraulic equipment of this type includes a pump unit 5E or the like for creating hydraulic pressure in the system. It is a particular feature of this invention that the pump unit Bil is so located on the panel assembly 5&3 that it is auto- -matically connected to a suitable rotary drive mechanism ywhen the assembly is mounted on the hea-d I. In addition to the pump unit 6i), various valves and the like are employed to control flow of the hydraulic liquid.

In connection with the drive for the pump unit Eil, it will be observed that the head Iii of the hydraulic unit here shown is provided with a second wall 62 behind and spaced from the end wall 22. If desired, a second bearing 56 for the rearward end of spindle I4 may be carried by wall S2. A gear 63 is keyed to the spindle I4 between walls 22 and e2, and this gear meshes with a gear 6B having oppositely extending stud shafts 'I0 and 'I2 which are rotatably supported in Walls 22 and G2 by bearings 'I and 'Iii respectively. Stub shaft 753 extends forwardly through wall 22 and the projecting end thereof is equipped with a coupling I6 which is positioned to receive the driven shaft 'I8 of the pump unit Eil automatically when the panel assembly 55 is mounted on the head I0.

I have here shown the pump unit mounted on the inside of the panel assembly 5E so that it is disposed bodily in the fluid reservoir of the hydraulic systems. The driven shaft 78 is adapted to telescope into the coupling IS and it conveniently is provided with splines which interengage correspondnigly shaped splines in the coupling to establish a direct rotary drive therebetween.

To connect the pump unit 60 with the drive mechanism, it is merely necessary to place the panel assembly 55 against the side of housing I0 and then push the entire assembly to the right as viewed in Figs. 1 and 2 to engage the driven shaft "I8 with the driving coupling 16. After the pump unit 6@ has been connected to the power drive in the manner described, the panel assembly can be easily and quickly bolted to the housing.

The machine here shown is adapted to advance rapidly on a traverse stroke to bring the tool up to the work and to then advance relatively slowly on a feed stroke as the tool is brought against the work. After the feeding stroke is completed, the head is withdrawn rapidly to its initial posi- Consequently, the panel assembly 56 is equipped with hydraulic instrumentalities and electrical controls for effecting the series of movements described below.

Reference is now had to Fig. 5 which shows the hydraulic equipment for operating the machine. The pump unit 60 here shown is a dual unit which comprises a traverse pump 80 and a feed pump 82. The traverse pump 80 has an inlet 04 and an outlet 85 and is adapted to charge a relatively large volume of liquid under relatively low pressure to the hydraulic system. rihe feed pump 82 has an inlet 88 and an outlet 50 and is adapted to charge a relatively low volume of liquid under relatively high pressure to the hydraulic system. Both pumps 80 and 82 conveniently can be driven simultaneously from the same shaft 'i8 according to conventional practice. As suggested, the pump unit 60 is mounted on the inside of a panel 92.

The discharge outlet 86 of the traverse pump 80 is connected to the inlet port 94 of a conventional spring-centered, solenoid pilot-operated four-way valve 96 by a conduit S8. A relief valve |00 in conduit 58 limits maximum pressure in the conduit to about 325 lbs. per square inch. The discharge outlet 9i) of feed pump 82 is connected to the inlet I 02 of a conventional two-way valve |84 by a conduit |06. A relief valve |68 in conduit |06 limits maximum pressure therein to about 1000 lbs. per square inch. Also, the discharge outlet 60 is connected to the pilot port I I0 of four-way valve 96 by a branch conduit I |2. Thus, since feed pump 82 is continuously operated, it maintains pilot pressure at all times on the four-way valve 96.

The four-way valve 96 has two discharge ports I3 and I I4 which open into the tank or reservoir. Also, the four-way valve 96 has two discharge ports I 6 and l I 8 which connect to opposite ends vof the cylinder 36. Specifically, outlet port I I6 is connected by conduits and I 22 to the passage 44 at the forward end of cylinder 36, and outlet port IIS is connected by conduits |24 and |26 to the passage 46 which communicates with the rearward end of the cylinder. A relief valve |28 at the juncture of conduits |24 and |26 limits i maximum pressure therein to about 200 lbs. per square inch.

Cylinder 36 and head I0 associated therewith can be made to advance or retract relatively rapidly by operating valve S6 to connect the inlet port 94 either with the port II5 or the port ||8. When the inlet port 94 is connected to outlet port H6, hydraulic liquid from traverse pump 86 is directed to the forward end of cylinder 36 and the unit advances. On the other hand, when inlet port 94 is connected to outlet port I I8, hydraulic liquid from traverse pump 80 is directed to the rearward end of cylinder 36 and the head retracts.

The two-way valve |64 is provided with two outlet or discharge ports |30 and |32. Outlet |30 is connected directly to the tank through a pressure-relief valve |34 which normally is set to yield at a pressure of about 50 lbs. per square inch. The other outlet |32 is connected to the inlet |36 of a conventional flow-control valve |38 by a conduit |48. The flow-control valve |38 is provided with two outlets |4I and |42. Outlet |4| discharges excess liquid in the valve to the tank and outlet |42 is connected by conduit |44 to the conduit |22 which leads to the forward end of cylinder 36. When two-way valve |64 is positioned to effect communication between inlet |62 and outlet |30, the output of feed pump 82 is directed back into the tank through relief valve |34. However, the latter functions to maintain at least lbs. pressure in conduits |06 and ||2 and thusmaintains operating pressure on the pilot of four-way valve 96. On the other hand, when two-way valve |04 is positioned to effect communication between inlet |02 and outlet |32, liquid from the feed pump 82 is directed through conduit |40, flow-control valve |38, conduit |44, and passage 44 to the forward end of the cylinder 36 to advance the latter on the feed stroke.

The flow-control valve |38 regulates the rate of flow of liquid to the cylinder 36 and thus determines the rate of advancement of the unit. Most valves of this type are equipped with a manual control |46 which is adjustable to regulate the rate of flow through the valve. Valves of this type are conventional and their construction well known; consequently a detailed disclosure or description is not essential.

Reference is now had to Fig. 6 which shows the electrical circuit for controlling operation of the hydraulic equipment hereinabove described. Current is conducted to the apparatus from any suitable source of electrical energy through line |48 and is returned to the source through line |50.

Motor 26 is equipped with the usual starter,

' and current from the line I 48 flows to the starter coil |52 through line |54. From the coil |52, current ows to the negative side of the circuit through lines |56 and |58, switch |60, line |6I, and stop switch |62. Switch |60 is operated mechanically by the coil |52, as indicated in the drawing, and stop switch |60 is manually operl ated to control flow of current through the coil |52 and through the entire electrical circuit. Switch |60 is normally open, and switch |62 is normally closed as shown.

The entire circuit is energized by a starting switch |64 which by-passes switch |60. Current from line |56 flows through lines |66 and |68 through switch |64, and thence through line |10 to switch |62 and line |50. Manifestly the starting switch |64 is normally open, and it will be readily apparent that no current will flow through the starter |52 as long as the starting switch remains open. Starting switch |64 is manually operated; and as soon as it is closed, current flows through the starter |52. As soon as the circuit is completed through the starter |52, switch |60 is closed by the starter coil |52 and it remains closed after the starting switch |64 is released and until the stop switch |62 is opened.

When current is flowing through the starter |52, motor 26 is energized and it continuously drives the tool spindle I4 as well as both the traverse pump and the feed pump 82. The head I6 is normally retracted as shown in Figs. 1 and 2. The four-way valve 96 normally is positicned to direct the output of traverse pump 80 to the tank discharge port I3. The two-way valve |64 normally is positioned to direct the output of feed pump 82 to the tank discharge port |30. Of course as suggested, the feed pump acts at all times through the conduit I I2 to maintain operating pressure on the solenoid of four-way valve 96. Thus, with the head I0 retracted and the valves 56 and |64 positioned in the manner described, the output of traverse pump 80 and feed pump 82 is merely circulated through the valves and back to the tank. Also, it should be noted that automatic operation of the machine is controlled by three limit switches: LSI, LSZ, and LS3 (Figs. 1 and 6); and, when the head I0 is fully retracted, the normally open limit switch LSI is `switches CRI-I and CRI- 2. .control relay CRI is energized in the manner declosed by a dog |12. The spindle I4 and the tool driven thereby are continuously rotated, of course, and the two pumps 80 and 82 are continuously driven at all times when the machine is in operation but the machine does not begin its cycle of operation until the normally open, manually operated, cycle start switch |14 is closed.

When the cycle start switch |14 is closed, current flows from line |48 through line |16, line |18, control relay CRI, line |82, normally closed emergency return switch |84, line |86, normally vclosed limit switch LS2, lines |88 and |90, the mechanicaliy closed limit switch LSi, line |82, the manuallyclosed cycle start switch |14, lines |94, |96, and |98, and thence to the negative side of the circuit in the manner hereinabove described.

Control relay CRI has two normally open As soon as the scribed above, the two switches 'CRI-,I and CRI-2 are closed. Thereafter switch CRI-I acts as a holding circuit to maintain the control I relay CRI energized after the manually operated -cycle start switch |14 has been released and after the limit switch LSI has been opened by initial advancement of the head I0. In connection with the foregoing it will be readily apparent that energization of relay CRI and the consequent closing of switch CRI- I permits current to flow from line |88 through line 200, switch CRI-I, and lines 202 and 204 to line |96, and thence to the negative side of the circuit. Switch CRI-2 controls the forward solenoid 206 of four-way valve 86; and as soon as this switch is closed, current Iiows from line |16 through lines 208, '2|0, 2|2, and 2 I4, switch CRI-2, line 2 I 6, solenoid 206, and lines 2I8, 220, 222, 224, 226, and 228 to line 204 and thence to the negative side of the circuit.

Thus the forward solenoid 286 of four-way valve 9'6 is energized as soon as the circuit is closed through control relay CRI and the forward solenoid remains energized until the circuit .through control relay CRI is broken. When soie- `noid 206 is energized it operates the four-way valve 96 to connect the inlet port 84 to discharge port II6 and to connect the port |I4 to port |58. The output of transverse pump 80 then flows .through the four-way valve to the forward end of cylinder 36. Hydraulic pressure in the forward end of the cylinder 36 causes the head to afd-- Vance. Fluid trapped in the cylinder 36 behind piston 38 is discharged to the tank in an obvious manner. Relatively little pressure is required,

-since the hydraulic liquid merely acts to advance the head sufficiently to bring the tool up to the work. The full capacity ofthe traverse pump 88 is utilized so that the initial traverse movement of the head is relatively rapid. At this stage in Ythe operation, the two-way valve |04 is unaffected and the output of feed pump 82 continues to be circulated through the two-way valve to the tank.

yThese two switches LSZ and LS2a are mechane ically connected for mutual operation. As soon -as the limit switch is operated by dog 238, limit switch LS2 is opened to break the circuit through control relay CRI and limit switch LSZa is closed 4to complete a circuit through control relay CR2. Current then flows from line 208 through line 232, control relay CR2, line 234, the normally closed relay switch CR3--2, line 236, the normally closed limit switch LS3a, lines 238 and 248, the mechanically closed limit switch LSZa, and line 242 to line 228 and thence to the negative side of the circuit. Relay CR2 has two normally open switches, CR2-I and CR2- 2; and as soon as the relay is energized, these switches are closed.

Switch CR2-I is in a holding circuit for control relay CR2, and it serves to maintain the relay energized after limit switch LS2a has opened by advancement of the switch actuator beyond dog 238. Thus as soon as control relay CR2 is energized, current also flows from line 238 through line 244, switch CR2-I, and line 246 to line 226 and thence to the negative side of the circuit. From the above it will be readily ap-1 parent that after limit switch LS2a has opened, current will continue to flow through switch CR2- I to maintain control relay CR2 energized.

The other switch CR2-2 controls the solenoid 248 of two-way valve |04. As suggested, switch CR2-2 is closed as soon as relay CR2 is enerF gized, and current ythen flows from line 2|? through lines 258 and 252, switch CR2-2,y line 254, solenoid 248, and lines 256 and 258 to line 228 and thence to the negative side of the circuit.

As soon as control relay CRI i's de-energizei by operation of limit switch LS2, the relay switch CRS-2 is opened to break the circuit through the forward solenoid 206 of four-way valve 96. The spring-centered spool of the four-way valve 97E is then returned automatically to its normal position to again connect the inlet port 84 to thc tank port |I2. When this occurs, the output of traverse pump 86 is again circulated through the four-way valve 96 directly to the tank. As suggested, simultaneously with the above operation the relay switch CR2-2 is closed to energize the solenoid 248 of two-Way valve |84. Operation of the two-way valve |04 connects the inlet port |02 with outlet port |32 and directs the output of feed pump 82 to the forward end of the cylinder 35 through the flow-control valve |38. The

, feed pump 82 supplies relatively high hydraulic pressure to the cylinder to advance the head I3 during that portion of the cycle of operation when the tools are cutting through the work. Also. advancement of the head during this portion of the cycle of operation is relatively slow and the rate of movement is controlled by the ow-con trol valve |38 in the manner hereinabove described.

The head I0 continues to advance until limit switch LS3 engages dog 260. As shown in Fig. 6, this limit switch comprises a normally open switch designated L83 and a normally closed switch designated LSSa, and these switches are mechanicaly interconnected for mutual operation. As soon as the actuating arm of the switch engages dog 260, switch LS3 is closed and switch LS8a is opened.

As described above, switch LS3a is in the circuit which controls relay CR2; and as soon as this switch is opened, relay CR2 is de-energized. Simultaneously, relay switch CR2-2 is opened and the solenoid 248 of the two-way valve |04 is de-energized. De-energization of solenoid 248 permits the two-wayY valve |04 to return to its normal position so that the output of feed pump 82 is again circulated directly to the tank.

Also, as soon as limit switch L53 is closed, a circuit is completed from line 2I0 through line 262, control relay CRB, line 264 and 266, the normally closed limit switch LSIa. which is mechani- 9 cally connected to limit switch LSI, lines 283 and 218, mechanically closed limit switch LS3 and line 212 to line 224 and thence to the negative side of the circuit.

Control relay CRB has a normally open switch CR3-I, a normally closed switch CRB- 2, and a normally open switch CRS-3; and as soon as the relay is energized by closure of limit switch LS3, switches CR3-I and CRS-3 are closed and switch CRB-2 is opened. Relay CR3 controls the return movement of the head I8 and remains energized until the head is fully retracted.

Switch CR3-2 is in the circuit which controls relay CRZ, and it thus remains open to prevent energization of relay CR2 when limit switch LSZ rides over dog 238 on the return stroke of the head I8.

Switch CRS-I completes a holding circuit which maintains relay CR3 energized after the head I6 has begun its return stroke and limit switch CR3 has backed away from and released the actuating dog 268. In this connection it will be readily apparent that energization of the relay CR3 also permits current to ilow from line 288 through line 214, switch CR3|, and line 218 to line 222 and thence to the negative side of the circuit. Thus, switch CR3-I will maintain relay CRS energized even after limit switch LS3 has opened.

Switch CRS-3 controls the return solenoid 218 of four-way valve 98. Thus as soon as relay CRS is energized, current can flow from line 288 through line 23d, switch CR3-3, line 282, solenoid 218, and line 284 to line 258 and thence to the negative side of the circuit. Solenoid 218 actuates four-way valve 95 to effect communica tion between inlet port 94 and outlet port H8 and between the two ports I2 and H8. Thus, as soon as the solenoid 258 has been energized, the output of traverse pump 88 is directed to the rearward end of cylinder 38 and the forward end of the cylinder is connected to the tank. A rapid return is desired, and the full capacity of traverse pump 80 is therefore available to retract the cylinder 38. In this connection, it will be readily apparent that iiuid trapped in the cylinder head of piston 38 is discharged through the four-way valve 93 to the tank.

The head I8 continues to retract until limit switch LSI again engages the operating dog |12. When this occurs, limit switch LSI is closed to set up a preparatory circuit through control relay CRI and limit switch LSIa is opened to break the circuit through control relay CR3. As soon as' the latter relay is de-energized, four-way valve 96 is again returned automatically to a neutral position to circulate the output of traverse pump 88 directly' to the tank. The machine has then completed its cycle of operation, and it will remain in this position until the cycle start switch |14 is again closed.

The machine can be returned to its initial position in any stage in its operation by manual manipulation of the emergency return switch 288 which is mechanically connected to the switch |84 hereinabove referred to. Switch 288 is normally open and switch 284 is normally closed. Also, it will be observed that one side of the normally open switch 288 is connected to line 264 by line 288 and that the other side of switch 288 is connected to line |98 by line 298. As suggested, switch 288 is manually operated; and, as soon as it is closed, a circuit is completed through the control relay CR3 to retract the head I0 in the manner hereinabove described. Since switch |84 is opened simultaneously with the closure of switch 28E, de-energization of control relay CRI is assured, and since relay switch CRS-2 is opened automatically when control relay CR3 is energized, de-energization of control relay CRZ also is assured upon operation of the emergency return switch. Thus the head I8 is returned automatically when emergency return switch 288 is operated, regardless of its position at the time the switch is operated.

The panel 92 preferably is in the form of a casting, and most of the conduits which form the hydraulic circuit can be formed directly in the casting to minimize leakage from the circuit or danger of rupture in any of the conduits. It is particularly desirable to form the conduits |22 and |28 directly in the panel and to so locate these conduits that they automatically register with the passages 44 and 46 at opposite ends of the cylinder 38 when the panel is mounted on the head i8. This construction eliminates the necessity of making hydraulic connections at these points and assures precise alignment of the conduits with the passages by the mere mecl'anical operation of fastening the panel on the head. However, it will be readily apparent that, if desired, the panel 92 can be made merely of sheet metal and the various hydraulic instrumentali-- ties mounted thereon and connected by suitable tubular conduits.

Also, the electrical connections preferably are made through an electric terminal block 292 mounted on the panel as shown in Fig. 3 in order to maintain the panel assembly as much of a unit as possible and to reduce to a minimum the num-- ber of electrical connections that must be made when the panel assembly is mounted on or removed from the machine. All the hydraulic equipment except the pump assembly 68 and alll i the electrical connections to the panel preferably are made on the outside of the panel 92. All of the control equipment except the manual actuator |48 of the now-control valve |38 are con-l cealed behind a cover 294 (Fig. l). The cover 294 is suitably fastened to .the panel 92, and it is provided with an opening 296 through which thel manual actuator |46 projects for convenient access to the operator.

When the mounting arrangement hereinabove' described is adopted, a panel assembly can be removed from the machine in a very few minutes merely by disconnecting a few electrical connections at the terminal block 292 and disengaging the panel 92 from the head I0. When the hydraulic conduits which serve the cylinder 38 are formed directly in the panel in the manner here-y inabove suggested, that portion of the hydraulic' circuit which connects with parts outside the panel are automatically broken merely by removing the panel from the head. Also, the only mechanical connection outside the panel, i. e., the connection between the pump assembly and the driving coupling 16, is broken automatically by removal of the panel from the head. No parts of the machine need be removed or disassembled in order to remove the panel assembly. Thus the mounting arrangement here shown is exceedinly convenient and will reduce from a matter of hours to a matter of minutes the time during which a machine is out of operation in the event failure occurs in the hydraulic or electrical operating or control circuits.

Having thus described the invention, I claim:

1. A mounting arrangement for hydraulic machinery of the type having a `slidable part, a hydraulic motor for actuating said part and having ports through which hydraulic liquid passes to and from the motor, a tank for hydraulic liquid, and a drive shaft associated with said tank, a unitary assembly comprising a panel adapted to be removably attached to a wall of said tank, instrumentalities for circulating and controlling ow of hydraulic liquid carried by said panel, said instrumentalities including passages for delivering hydraulic liquid to and receiving hydraulic liquid from said hydraulic motor, said passages so located on the panel as to align eX- actly with and to superimpose on the ports which service said hydraulic motor when the panel is fastened to the tank, said instrumentalities also including a pump on the inner side of the panel adapted to be disposel within the tank when the panel is fastened thereto, said Vpump having a driven shaft and said driven shaft being located so as to interconnect with the drive shaft automatically when the panel is fastened to the tank.

2. A mounting arrangement for hydraulic machinery of the type having a slidable part, a hydraulic motor for actuating said part and having ports through which liquid passes to and from the motor, and a tank for hydraulic liquid, a unitary assembly comprising a panel adapted to be removably attached to the wall of the tank, instrumentalities for circulating and controlling flow of hydraulic liquid carried by said panel and including passages for delivering hydraulic liquid vto and receiving hydraulic liquid from said hydraulic motor, said passages so located on the panel as to align exactly with and to superimpose on the ports which service said hydraulic motor when the panel is fastened to the tank.

l 3. A mounting arrangement for hydraulic machinery of the type having a slidable part, a hydraulic motor for actuating said part and having ports through which liquid passes to and from the motor, and a tank for hydraulic liquid, a unitary assembly including a panel adapted to vbe removably attached to the wall of said tank, hydraulic pump means on said panel, passages for receiving hydraulic liquid from said pump means and for delivering hydraulic liquid to said hydraulic motor, said passages having openings so located on the panel as to align exactly with and to superimpose on the ports which servicevsaid hydraulic motor when the panel is fastened to the tank, and instrumentalities mounted on and carried by said panel for circulating and controlling flow of hydraulic liquid between Vthe pump and said hydraulic motor.

f4. A mounting arrangement for hydraulic mai chinery of the type having a slidable part, a hydraulic motor for actuating said part and having ports through which hydraulic liquid passes to and from the motor, and a tank for hydraulic liquid, a unitary assembly comprising a panel adapted to be removably attached to the wall of the tank, hydraulic pump means on the inner side of the panel adapted to be disposed within the tank when the panel is fastened thereto, a iluid circulating system associated with the panel for delivering hydraulic liquid from said pump means to the ports which service said hydraulic motor, Valve means for controlling the direction of flow of hydraulic liquid through said system, and means operable by movement of said slidable part for controlling said valve means whereby to operate said slidable part through a predetermined cycle of operation.

5. A mounting arrangement for hydraulic machinery of the type having a slidable part, a hydraulic motor for actuating'said part and having ports through which hydraulic liquid passes to and from the motor, and a tank for hydraulic liquid, a unitary assembly comprising a panel adapted to be removably attached to the wall of the tank, hydraulic pump means on the inner Side of the panel adapted to be disposed within the tank when the panel -is fastened thereto, a fluid circulating system associated with the panel for delivering hydraulic liquid from said pump means to the ports which service said hydraulic motor, electrically controlled valve means for controlling the direction of ow of hydraulic liquid through said system, and an electrical circuit including the electric controls of said valve means and limit switches carried by the panel, said limit switches being actuated by movement of said slidable part and operable to selectively energize th-e electric controls of said valve means to actuate said slidable part in a predetermined manner.

CHITE S. LEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

